Consolidating p17 datingxs com
Early models of associative learning suggested that extinction was due to the “unlearning” or “erasure” of the original CS–US association (e.g., Rescorla and Wagner 1972).
However, it is now more widely accepted that the reduced CR following extinction reflects new learning of a CS–no US association that inhibits the expression of the original CS–US association (e.g., Bouton 2002).
Not only are these findings important theoretically, the observed developmental differences in extinction also have significant clinical implications.
To examine opioid involvement in extinction in the developing rat, we gave P17 and P24 rats a systemic injection of saline or naloxone (5 mg/kg) 10 min before extinction training.On the other hand, finding that naloxone affects extinction acquisition in P17 rat is quite novel considering that no previous pharmacological agent has been shown to affect extinction at this age (i.e., neither MK-801 nor FG7142 affect extinction at this age).Therefore, follow-up experiments in this study focused on extinction in P17 rats.The primary evidence for this view comes from behavioral studies that show performance to an extinguished CS can recover without any retraining (e.g., spontaneous recovery, renewal, and reinstatement).Additionally, we know that extinction involves inhibition because reducing γ-amino butyric acid (GABA) inhibitory activity by pretest injections of the GABA receptor inverse agonist FG7142 reverses extinction (Kandel 2001).